Refrigeration systems using high pressure receivers



J. R. HARNISH REFRIGERATION SYSTEMS USING HIGH PRESSURE RECEIVERS Filed May 23, 1966 2 Sheets-Sheet 1 mowmwmazoo A Q 528% u lll u xouzu m1 460 H E4 w moon; 3

R o mm 6 m L n K Alli 460 u mr All N m2 m v 9 $850 ll. immuim l INVENTOR= JAMES R.HARNISH, BYWQ ATTORNEY Nov. 7, 1967 J.R.HARN1SH 3,350,898

REFRIGERATION SYSTEMS USING HIGH PRESSURE RECEIVERS Filed May 25, 1966 2 Sheets-Sheet 2 FHlZ.

|NVENTOR= JAMESFKHARNSH, I BYQSEM2h7 v@-; ATTORNEY United States Patent 3,350,898 REFRIGERATION SYSTEMS USING HIGH PRESSURE RECEIVERS James R. Hamish, Staunton, Va., assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed May 23, 1966, Ser. No. 552,133 6 Claims. (Cl. 62-218) This invention relates to refrigeration systems using high pressure receivers, and has as an object to adjust an expansion valve in accordance with changes in the level of refrigerant liquid within such a receiver.

My copending application, Ser. No. 447,008, filed Apr. 9, 1965, issued as Patent No. 3,264,837, discloses the advantages of using an expansion valve which supplies refrigerant to an associated evaporator at the rate at which the refrigerant is condensed within an associated condenser, thus keeping the condenser adequately drained, and overfeeding the evaporator so that all of its internal surface is thoroughly wetted. The unevaporated refrigerant flowing from the evaporator is prevented from flowing into the associated compressor, by flowing it into an accumulator where it is evaporated by heat from the high pressure liquid, the latter being subcooled by this action. In that application, the excess refrigerant liquid flowing into the accumulator is evaporated by heat from a coil immersed in liquid within the accumulator, with the high pressure liquid flowing through that coil.

This invention uses a high pressure receiver to store liquid drained from a condenser, and adjusts the associated expansion valve in accordance with changes in the level of the liquid within the receiver. When the level of such liquid increases, the expansion valve is adjusted towards open position, and when the level of the liquid decreases, the expansion valve is adjusted towards closed position, with the expansion valve eflectively supplying refrigerant to the evaporator at the rate at which the refrigerant is condensed-within the condenser. Another feature of this invention is that the heat exchange coil arranged to heat the liquid within an accumulator, is

wrapped around the accumulator in heat exchange contact with its outer surface.

This invention will now be described with reference to the annexed drawings, of which FIG. 1 is a diagram.- matic view of a heat pump embodying this invention, and FIG. 2 is an enlarged view, in section, of the floatoperated pilot valve of FIG. 1.

A refrigerant compressor C is connected by discharge gas tube 10 to a conventional refrigerant reversal valve RV which is connected by tube 11 to one end of outdoor air coil 12,-and by tube 13 to one end of indoor air coil 14. The other end of the outdoor coil 12 is connected by tube 16 to check-valve .17 which is connected by tube 18 to high pressure receiver 19. The receiver 19 is connected by tube 20 to heat exchange coil 22 wrapped around a suction line accumulator 23 in heat exchange contact with the outer surface of the latter. The coil 22 is connected by tube 24 to expansion valve EV which is connected by tube 25, and by tube 26 to a check-valve 27 which is connected by tube 28 to the other end of the indoor coil 14.

The expansion valve EV is also connected by the tube 25 to check-valve 30 which is connected by tube 31 to the tube 16. The tube 28 is connected by tube 35 containing a check-valve 36 to the tube 18 between the check-valve 17 and the receiver 19. The reversal valve RV is cqnnected by tube 38 to the upper portion of the 3,350,898- Patented Nov. 7, 1967 accumulator 23 at one end of the latter. A suction gas tube 39 connects the upper portion of the accumulator 23 at the other end of the latter to the suction side of the compressor C, and has an intermediate portion 45 wrapped around the receiver 19 in heat exchange with the outer surface of the latter.

A conventional, float-operated, pilot valve 40 is connected by tube 41 to the top of the receiver 19, and a tube 42 connects the pilot valve 40 to the bottom of the receiver 19. The pilot valve 40 is connected by a tube 43 to piston chamber 44 of the expansion valve EV. The valve 40 may be a conventional Phillips pilot valve No. 270A, and the expansion valve EV may be a conventional Phillips expansion valve No. 801. The latter, and its operation are disclosed on pages 327-329 of the textbook Principles of Refrigeration by R. J. Dossat, published in 1961 by John Wiley & Sons.

Referring now to FIG. 2, the pilot valve 40 has a float chamber 50 connecting with the tubes 41 and 42, and within which is a float 51 connected to a rod 52 which is attached to the top of a float block 53. The latter is pivoted between its top and bottom about a lever pin 54, and its bottom is attached by a pivot pin 56 to a link 55. The latter is attached by a pin 57 to a nut 58 threaded on one end of rod 59. A needle valve 60 is formed on the other end of the rod 59. The valve 60 is slid-able within a nut 61 threaded in wall 62 of the valve 40, and its outer end converges towards an orifice 63 in the outer end of the nut 61, the edge of the orifice forming a seat for the valve 60. The orifice 63 connects with a passage 64 which connects with the tube 43. A coiled spring 65 extends between the nuts 58 and 61, and biases the valve 60 towards unseated position.

The needle valve 60, when unseated, supplies high pressure refrigerant liquid from the float chamber 50, through the tube 43 into the piston chamber 44 of the expansion valve EV. A rise in the level of the liquid within the chamber 50 causes the float 51 to move the valve 60 towards unseated position, and vice versa.

Cooling operation The solid-line arrows alongside the tubes show the direction of refrigerant flow during cooling operation. Discharge gas from the compressor C flows through the tube 10, the reversal valve RV and the tube 11 into the outdoor coil 12 operating as a condenser coil. Liquid flows from the coil 12 through the tube 16, the check-valve 17 and the tube 18 into the receiver 19. Liquid flows from the receiver 19 through the tube 20, the heat exch-ange coil 22, the tube 24, the expansion valve EV, the tubes 25 and 26, the check-valve 27 and the tube 28 into the indoor coil 14 operating as an evaporator coil. Gas and unevaporated liquid flow from the coil 14 through the tube 13, the reversal valve RV and the tube 38 into the accumulator 23. Gas separated from the liquid within the accumulator 23 flows through the suction gas tube 39 to the suction side of the compressor C.

The heat pump preferably would be overcharged with refrigerant so that there would always be a quantity of refrigerant within the accumulator. Heat from the high pressure liquid flowing through the coil 22 heats the liquid within the accumulator, and evaporates an amount of such liquid equal to the amount of unevaporated liquid flowing from the coil 14, the high pressure liquid being s-ubcooled by this action. Heat from the high pressure liquid within the receiver 19 through the contact of the latter with the coil portion 45 of the suction gas tube 39,

evaporates any refrigerant liquid entering the suction gas tube 39, the high pressure liquid being further subcooled by this action.

The level of the refrigerant liquid within the receiver 19 varies in accordance with the quantity of liquid condensed within the outdoor coil 12. The pilot valve 49 responds to changes in the level of the liquid within the receiver 19, and adjusts the expansion valve EV towards open position on an increase in liquid level, and adjusts the expansion valve EV towards closed position on a decrease in the level of the liquid, thus maintaining the liquid level substantially constant, and causing the expansion valve EV to feed the indoor coil 14 at the rate at which the refrigerant is condensed within the coil 12. The coil 12 is adequately drained, and the coil 14 is overfed since the quantity of condensed liquid is that evaporated within the coil 14, and within the accumulator by the I coil 22.

This invention could be embodied in a non-reversible cooling system which would operate as described in the foregoing except that the reversal and check-valves would be omitted.

Heating operation The dashed-line arrows alongside the tubes show the direction of refrigerant flow during heating operation. Discharge gas from the compressor C flows through the tube 10, the reversal valve RV and the tube 13 into the indoor coil 14 operating as a condenser coil. Liquid flows from the coil 14 through the tube 35, the check-valve 36, and the tube 18 into the receiver 19. Liquid flows from the receiver 19 through the tube 20, the heat exchange coil 22, the tube 24, the expansion valve EV, the tube 25, the check-valve and the tubes 31 and 16 into the outdoor coil :12 operating as an evaporator coil. Gas and unevaporated liquid flow from the coil 12 through the tube 11, the reversal valve RV and the tube 38 into the accumulator 23. Gas separated from the liquid within the accumulator 23 flows through the suction gas tube 39 to the suction side of the compressor C.

Heat from the high pressure liquid flowing through the coil 22 evaporates the unevaporated refrigerant liquid flowing from the coil 12 into the accumulator 23, the high pressure liquid being subcooled by this action. Heat from the high pressure liquid within the receiver 19 superheats through the heat exchange contact of its outer surface with the coil portion 45 of the suction g-as tube 39, the suction gas flowing through the coil portion 45, the high pressure liquid being further subcooled by this action.

The level of the refrigerant liquid within the receiver 19 varies in accordance with the quantity of liquid condensed within the indoor coil 14. The pilot valve 40 responds to changes in the level of the liquid within the receiver 19, and adjusts the expansion valve EV towards open position on an increase in the liquid level, and adjusts the expansion valve EV towards closed position on a decrease in the liquid level, thus maintaining the liquid level substantially constant, and causing the expansion valve EV to feed the outdoor coil 12 at the rate at which refrigerant is condensed within the indoor coil 14. The coil 14 is adequately drained, and the outdoor coil 12 is overfed.

What is claimed is:

1. A refrigeration system comprising a refrigerant compressor, a condenser, a receiver, a heat exchange coil, an expansion valve, an evaporator, and a suction line accumulator connected in the order named in a refrigeration circuit, said heat exchange coil being arranged to heat liquid within said accumulator, and means including means responsive to changes in the level of refrigerant liquid within said receiver connected to said expansion valve for adjusting said expansion valve towards open position on an increase in liquid level, and towards closed position on a decrease in liquid level, said system being overcharged with refrigerant so that there is always a quantity of refrigerant liquid within said accumulator, said expansion valve overfeeding said evaporator so that unevaporated liquid flows from the latter into said accumulator, said heat exchange coil being arranged to evaporate refrigerant liquid within said accumulator at substantially the same rate at which unevaporated refrigerant liquid flows from said evaporator into said accumulator.

2. A refrigeration system as claimed in claim 1 in which said heat exchange coil is wrapped around said accumulator in heat exchange contact with the outer surface of said accumulator.

3. A refrigeration system comprising a refrigerant compressor, a condenser, a heat exchange coil, an expansion valve, an evaporator, and a suction line accumulator connected in the order named in a refrigeration circuit, said heat exchange coil being wrapped around said accumulator in heat exchange contact with the outer surface of said accumulator, and means including means connected to said expansion valve for adjusting said expansion valve to supply refrigerant from said heat exchange coil to said evaporator at the rate at which the refrigerant is condensed within said condenser.

4. A heat pump comprising a refrigerant compressor, reversal valve means, a discharge gas tube connecting the discharge side of said compressor to said reversal means, an outdoor coil, a second tube connecting said reversal means to said outdoor coil, an indoor coil, a third tube connecting said reversal means to said indoor coil, a receiver, a fourth tube containing a first check-valve connecting said outdoor coil to said receiver, means including a fifth tube containing a second check-valve connecting said indoor coil to said receiver, a heat exchange coil, a sixth tube connecting said receiver to said heat exchange coil, an expansion valve, a seventh tube connecting said heat exchange coil to said expansion valve, means including an eighth tube containing a third check-valve connecting said expansion valve to said indoor coil, means including a ninth tube containing a fourth check-valve connecting said expansion valve to said outdoor coil, a suction line accumulator, a tenth tube connecting said reversal means to said accumulator, a suction gas tube connecting said accumulator to the suction side of said compressor, said heat exchange coil being arranged to heat liquid within said accumulator, and means including means responsive to changes in the level of liquid within said receiver connected to said expansion valve for adjusting said expansion valve towards open position on an increase in liquid level, and towards closed position on a decrease in liquid level.

5. A heat pump as claimed in claim 4 in which said heat exchange coil is wrapped around said accumulator in heat exchange contact with the outer surface of said accumulator.

6. A heat pump comprising a refrigerant compressor, reversal valve means, a discharge gas tube connecting said reversal means to the discharge side of said compressor, an outdoor coil, a second tube connecting said reversal means to said outdoor coil, an indoor coil, a third tube connecting said reversal means to said indoor coil, a heat exchange coil, means including a fourth tube containing a first check-valve connecting said outdoor coil to said heat exchange coil, means including a fifth tube containing a second check-valve connecting said indoor coil to said heat exchange coil, an expansion valve, a sixth tube connecting said heat exchange coil to said expansion valve, means including a seventh tube containing a third checkvalve connecting said expansion valve to said indoor coil, means including an eighth tube containing a fourth checkvalve connecting said expansion valve to said outdoor coil, a suction line accumulator, a ninth tube connecting said reversal means to said accumulator, a suction gas tube connecting said accumulator to the suction side of said compressor, said heat exchange coil being wrapped around said accumulator in heat exchange contact with the outer surface of said accumulator, and means including means connected to said expansion valve for adjusting said expansion valve to supply refrigerant from said heat exchange coil to the one of said indoor or outdoor coils Which is operating as an evaporator coil at the rate at which the refrigerant is condensed Within the one of said outdoor or indoor coils which is operating as a condenser coil.

6 References Cited UNITED STATES PATENTS 2,016,056 10/1935 Small 622l8 2,735,272 2/1956 Lange 62-218 2,966,043 12/1960 Ross 6'2-218 WILLIAM J. WYE, Primary Examiner. 

1. A REFRIGERATION SYSTEM COMPRISING A REFRIGERANT COMPRESSOR, A CONDENSER, A RECEIVER, A HEAT EXCHANGE COIL, AN EXPANSION VALVE, AN EVAPORATOR, AND A SUCTION LINE ACCUMULATOR CONNECTED IN THE ORDER NAMED IN A REFRIGERATION CIRCUIT, SAID HEAT EXCHANGE COIL BEING ARRANGED TO HEAT LIQUID WITHIN SAID ACCUMULATOR, AND MEANS INCLUDING MEANS RESPONSIVE TO CHANGES IN THE LEVEL OF REFRIGERANT LIQUID WITHIN SAID RECEIVER CONNECTED TO SAID EXPANSION VALVE FOR ADJUSTING SAID EXPANSION VALVE TOWARDS OPEN POSITION ON AN INCREASE IN LIQUID LEVEL, AND TOWARDS CLOSED POSITION ON A DECREASE IN LIQUID LEVEL, SAID SYSTEM BEING OVERCHARGED WITH REFRIGERANT SO THAT THERE IS ALWAYS A QUANTITY OF REFRIGERANT LIQUID WITHIN SAID ACCUMULATOR, SAID EXPANSION VALVE OVERFEEDING SAID EVAPORATOR SO THAT UNEVAPORATED LIQUID FLOWS FROM THE LATTER INTO SAID ACCUMULATOR, SAID HEAT EXCHANGE COIL BEING ARRANGED TO EVAPORATE REFRIGERANT LIQUID WITHIN SAID ACCUMULATOR AT SUBSTANTIALLY THE SAME RATE AT WHICH UNEVAPORATED REFRIGERANT LIQUID FLOWS FROM SAID EVAPORATOR INTO SAID ACCUMULATOR. 